Apparatus for locating short circuits in electric lines.



No. 739,569. PATENTED SEPT. 22, 1903.

W. W. WOODRUFF. APPARATUS FOR LCCATINGSHCRT CIRCUITS IN ELECTRIC LINES.

APPLICATION FILED MAR. 19, 1903;

NC MODEL.

lilo.

UNITED STATES I Patented September 22, 1903.

PATENT OFFICE.

WILLIAM W. \VOODRU'FF, OF \VINOHESTER, KENTUCKY, ASSIGNOR OF ONE- HALF TO JAMES M. PIOKRELL, OF WINCHESTER, KENTUCKY.

APPARATUS FOR LOCATlNG SHORT CIRCUITS IN ELECTRlC LINES.

SPECIFICATION forming part of Letters Patent No. 739,569, dated September 22, 1903.

7 Application filed March 19,1903- Serial No. 148,585. (Nomodel-l To all whom it may concern: Be it known that I, WILLIAM W. W001) RUFF, a citizen of -the United States, residing at Winchester, in the county of Clark and State of Kentucky, have invented new and bination, and arrangement of parts hereinafter described, and particularly pointed out in the claims following the description, reference being had to the accompanying drawing, wherein the apparatus and its electrical connections are shown diagrammatically. Referring to the drawing, the numeral 1 indicates an instrument consisting of a suitable easing 2,in which is rotatably mounted a magnetic needle 3. Arranged within the casing on opposite sides of the needle are two electromagnets 4: and 5, each of which consists of an approximately semicircular core 6, of nonmagnetic material-such as copper, for exampleand wound in such manner that the north poles of the magnets stand in close proximity to the north pole of the needle 3 and between which the latter is exactly balanced. It follows, of course, that the south poles of said magnets will in like manner be in close proximity to the south pole of said needle and similarly balanced. In practice I prefer to arrange the adjacent ends of the' two magnets approximately one-eighth of an inch apart, so that there will exist a space of one-sixteenth of an inch between the end of the needle and the adjacent end of either of the magnets.

Each of the magnets have the The rheostat 7 comprises an annular series of pairs of contacts 8, each pair of which is connectedby a resistance 9, preferably of German silver, and to the first of said con tacts is connected by one of such resistances a primary contact 10. In practice each of the resistances 9 will have an electrical resistance equivalent to a circuit of live miles of No. 12 gage'copper wire. Pivoted centrally at 'one end relatively to the contacts is a hand The hands 11 and 12 areinsulated from each other and are independently and freely rotatable about their respective axes to place either in engagement with any one of their corresponding contacts. The hand 11 is in electrical connection with the primary contact let in any suitable manner-as, for example, by a wire 16. The primary contact8o 10 is connected by a wire 17 with one terminal of the helix of the magnet 5, the other terminal of the helix being connected to the binding-post 18. One. terminal of the helix of the electromagnct 4 is connected to the binding post 18, and the other terminal is connected by a wire 19 with a binding-post 20.

The numeral 22 designates a key or circuitclosing device, and said key is connected to the binding-post 18 by a wire 23. o The numeral 24 designates a double-pole switch, one side of which is connected to the key 22 by awire 25, and leading from said side of the switch is a wire 26, which is connected a stand of batteries 27. From the other side 5 of the batteries leadsa wire 28, which is connected to the other side of the switch 24:, and said side of the switch is connected by a wire 29 to a binding-post 21. The binding-posts 20 and 21 are respectively connected by wires I00 30 and 31 with the terminals ofthe circuit to be tested and measured. .7

' IO with the hand 12 of the rheostat '7.

I before referred to.

' the cores of said magnets.

The numeral 32 indicates a rheostat con structed in every Way similar to the rheostat 7, heretofore described, and comprises two annular series of contacts 33 and 34, primary 5 contacts 35 and 36, and two hands 37 and 38,

insulated from each other. The hand 37 is electrically connected by a wire 39, for example, with the primary contact 35, and the primary contact 36 is connected by a wire The hand 38 of the rheostat 32 is connected by a wire 41 with'one member of a single-pole switch 42, the other member of said switch being connected by a wire 43 with the binding-post 21, It will be evident if two currents of equalstrength be passed through the helices of the two electromagnets 4 and 5 that the magnetic needle 3 will be quickly and accurately balanced between the ends of For example, let it be assumed that the key 22 is depressed to close the circuit. The circuits may then be traced as follows: Passing from the batteries 27 the current passes through the wire 26,

25 through one side of the switch 24, through the wire 25, and by the latter to the key 22, thence over the wire 23 to the binding-post 18. At this point the current is divided, one portion passing to the magnet 4 and thence over the 0 wire 19 to the bindingpost 20, and it being assumed that the two binding-posts 20 and 21 have been connected in any suitable manner the current will then pass to the'binding-post 21, thence by wire 29 to the other side of the 35 double-pole switch 24, and from the latter by the wire 28 back to the battery, thereby completing the circuit through the magnet 4. The other portion of the current will pass to the magnet 5 and back by wire 17 to the pri- 0 mary contact 10 over the hand 11, and by contact 35, thence by the hand 38 and wire 41 to the switch 42, and thence by Wire 43 to the contact 21, and from the latter by the wire 29 to one side of the switch 24, and from the said switch 24 by the wire 28 back to the battery, thus completing the circuit through the magnet 5. The hands of the two rheostats being in the position shown, none of the resistances of either of said rheostats is in circuit, and hence the strength of the two -currehts is the same, and consequently the two magnets will be similarly effected, and the magnetic needle will be balanced between the ends of the cores of the two magnets in the manner described. As before stated, the

6o-construction of the rheostat 32 is identical with that of the rheostat 7; but the resistancesof the rheostat 32 are proportioned to measure the resistance of, say, No. 10 gage galvanized-iron wire. While the two rheostats are both included in what I term the resistance-circuit, it will be understood that at notime will both of them be operatively employed, the one being employed for testing circuits the lines of which consist of No. 12 gage copper wire and the other for testing circuits the lines of which consist of No. 10 gage galvanized-iron wire. Leading from the member 44 of the switch 42 is a wire 45, the terminal of which is connected to a flexible conductor 46, which in turn is connected to one end of the metallic pointer 47. The side 48 of the double-pole switch 24 is connected by a wire 49 to a binding-post 50, and leading from said bindingpost is a German-silver resistance-wire 51 the resistance of each inch or multiple of an inch whereof has been carefully and accurately determined, and a graduated scale is placed in close proximity to said wire 51 and is properly marked oif to indicate the different units of resistance throughout the length of said wire, or, more properly speaking, is marked to indicate the feet and inches corresponding to such units of resistance.

I will now describe the operation of my improved aparatus. Let in he assumed that a short circuit has been formed in the main line 30 31-say, for example, at a distance of twelve and one-half miles, ten yards, two feet, six inches from the station-and that it is desired to ascertain the distance from the station where such short circttit is located. The parts being in the position shown and the key 22 being closed, the resistance in the line-circuit would be greater than the resistance of the rheostat-circuit, and hence the current from the battery would pass through the magnet 5 and repel the north pole of the needle 3 and cause it to swing over against the end of the core of the magnet 4. Let it be assumed that the operator now moves the hand 11 into engagement with the second contact 8 of the rheostat 7, thus throwing into the rheostat circuit two resistance-coils which otter a resistance equal to a circuit of ten miles of No. 12 gage copper wire. It being'remembered that a short circuit has occurred in twelve and one-half miles and a fraction, the resistance of the line-circuit would still be greater than that of the rheostatcircuit, and hence the needle would remain in the deflected position before described. Let it be assumed that he then turns the hand 12 into engagement with the eighteenth contact 13 of the rheostat, thus throwing in the equivalent to the resistance of a circuit of two and one-fourth miles of N0. 12 gage copper wire. There would be then a total resistance in the rheostat-circuit of twelve and one-fourth miles, and the strength of the line-circuit and the resistance offered by the line-circuit would still preponderate over the resistance offered by the rheostat, and hence the needle would still remain in the described deflected position. The operator then moves the hand 12, say, up to the twenty-fourth contact 13, which would throw in resistance equivalent to a circuit of thirteen miles. It being remembered that the v short circuit has occurred at a distance verted to the magnet i, and thelatter would repel the north pole of the magnetic needle 3 and cause it to abut against the adjacent end of the core of the magnet 5. now knows that the short circuit has occurred at a distance from the station somewhere between twelve and one-half and thirteen miles therefrom. He now moves the hand 12 back over the contacts 13 until the magnetic needle 3 indicates that theresistance of the crossed circuit is greater than the resistance offered by the rheostat which will occur when the hand 12 has been moved back into engagement with the twentieth contact 13,'when the rheostat will oifer a total resistance equivalent to a circuit of twelve and one-half miles,

He then opens the switch 42, breaking the circuit between the wire 41 and 43, and taking the pointer 47 in his hand he places it upon the German-silver wire 51 near the bindingpost 50. The circuit now instead of passing from the wire il to the wire 43 passes by the wire 45, conductor 46, pointer 47, Germansilver wire 51, and the wire 4.9 to the side .48 of the switch,and from the latter by the wire 28 back to the battery.' He now moves the pointer over the German-silver wire until the needle 3 moves to normal position-that is to say, it is equally balanced between the poles of the two magnets, which of course occurs when the resistance of the rheostat circuit is equal to that of the short circuit. From the example employed herein to illustrate the operation of the apparatus we know that this occurs when the totol resistanceoftered by the rheostat 7 and the German-silver wire is equivalent to a copper circuit twelve and onehalf miles, ten yards, two feet, and six inches in length. I have shown that the resistance offered by the rheostat was equivalent to a circuit of twelve and one-half miles. Hence the resistance ofiered by the German-silver wire, or rather that portion 'of it which has been included in the circuit, is equivalent to ten yards, twofeet, and six inches. The exact location of the grounding or crossing of the circuits is thus accurately obtained. During the foregoing operation the two hands 37 and 38 of the rheostat 32 have remained in the position shown in the drawing and have simply served the purpose of forming a portion of the circuit. Should it be desired to locate the grounding or short-circuiting of a circuit consisting of a line formed of No. 10 gage galvanized-iron wire, the hands 11 and 12 of the rheostat 7 willbe turned to the po sition shown in the drawing, and the hands 37 and 38 of the rheostat 32 will be'employed in the manner before described relative to The operator man-silver bridge in the manner before described to locate the point where the'circuit the rheostat 7 in conjunction with the Ger-I is grounded or short-circuited. It will of course be understood that other rheostats could be included in the apparatus and employed in connection with lines formed of wires of dilferent conductivity'than those I have hereinbefore referred to and that also, if desired, only a single rheostat may be employed for use on'lines of a fixed conductivity.

In practice the contacts forming each series in the rheostats are consecutively numbered, and-the'rheostat thus not only constitutes a variable resistance, but, in fact, a rheostatic indicator. It will of course be understood that the described device is to be used in con-.

nection with metallic circuits-that is to say, consecutively consisting of a feed and return wire as contradistinguished from ground-circuits.

Having thus described the invention, what is claimed as new is-- 1. In an' apparatus of the character described, tbe combination with a line-circuit, of an oscillatory'needle, two approximately semicircular electromagn'ets arranged on 0pposite sides of the needle, the poles of said magnets being disposed in close proximity to the opposite poles of the needle, a rheostat, a battery and a branch circuit being in the line-circuit, and a branch circuit including the other magnet, the rheostat and said battery, the said needle being held in a state of equilibrium when the resistances of thelinecircuit and branch circuit are equal, substantially as described.

2. In an apparatus of the character described, the combination with a line-circuit, of an oscillatory needle, two approximately semicircular electromagnets arranged on opposite sides of the needle, the north pole of the needle being disposed between the north poles of thetwo magnets, and the south pole of said needle being in like manner disposed between the south poles of the magnets, a rheostat; a battery and a branch circuit, one of said magnets and the battery being in line circuit, and the branch circuit including the other magnet, the rheostat and said battery, the said needle being held in a state of equilibrium when the resistances of the line-circuit and branch circuit are equal, substantially as described.

3. In an apparatus of the character described the combination with a line-circuit, of an oscillatory magnetic needle pivoted centrally between its ends, two approximately semicircular electromagnets arranged on opposite sides of the needle, like poles of said magnets being disposed on opposite sides of the corresponding poles of the needle, a rheo; static indicator, a battery and a branch circuit, one of said magnets in the battery being in the line-circuit and the branch circuit including the other magnet, a rheostatic indicator and said battery, one portion of the .IOO

&

line-circuit serving as a feeder from the battery to both magnets, substantially as described.

4. In an apparatus of the character described, the combination with a line-circuit, of an oscillatory needle, two substantially semicircular electromagnets arranged on opposite sides of the needle, like poles of said magnets being arranged opposite each other, a rheostat, a battery and a branch circuit, one of said magnets and the battery beingin the line-circuit and the branch circuit including the other magnet, the rheostat and said battery,the said needle being held in a state of equilibrium when the resistances of the linecircuit and branch circuit are equal, substantially as described.

5. In an apparatus of the character described, the combination with a line-circuit, of an oscillatory needle, two electromagnets arranged on opposite sides of the needle, a plurality of rheostats each having a diiferent resistance from the other or others and arranged in series, a battery, anda branch circuit, one of said magnets and the battery being in the line-circuit and the branch circuit including the other magnet, the rheostats and said battery, substantially as described.

6. In' an apparatus of the character described, the combination with a line-circuit, of an oscillatory needle, two electromagnets arranged on opposite sides of the needle, a rheostat, a battery, and a branch circuit, one

of said magnets and the battery being in the -'ing it in connection with said pointer, substantially as described.

7. In an apparatus of the character described, the combination with a line-circuit, of an oscillatory needle, two electromagnets arranged on opposite sides of the needle, a rheostat, a battery, a branch circuit, one of said magnets and the battery being in the line-circuit and the branch circuit including the other magnet, the rheostat and said battery, and an auxiliary branch circuit connected to one side of the line-circuit and the said branch circuit and including a graduated resistance, and a metallic pointer movable thereover, substantially as described.

In testimony whereof I have hereunto set my hand in presence of two subscribing Wit- IIGSSGS.

WILLIAM W. WOODRUFF. Witnesses:

RUFUS LISLE, CHAS. B. STROTHER. 

